Thermal batteries provide a large amount of energy relative to their volume. These batteries, if hermetically sealed, can be stored substantially indefinitely without degradation of performance and can perform without preliminary preparation in many different environments. Thus, thermal batteries are a desirable source of power in a number of different applications. For example, thermal batteries are used in missile systems such as JDAM, Stinger, Javelin, as well as other systems such as aircraft ejector seats, and sonar buoys.
Thermal batteries contain materials that generally are inert and non-conductive until the battery is activated. Upon activation, the materials become molten and highly conductive. This allows the cathode to interact with the anode. The thermal battery materials are activated by igniting the battery. For example, a mixture of iron powder and potassium perchlorate may be used to ignite a battery. Once activated, the battery may continue to perform until the active material is exhausted or until the battery cools below the melting point of the electrolyte.
Understandably, it is desirable to test a thermal battery in a manner that does not ignite the battery. Typically, thermal batteries are tested using an ‘insulation resistance’ test. This test is performed by measuring the resistance in the path from one battery terminal to another and to the battery container. Unfortunately, this test may only disclose the existence of a short circuit in the battery. It generally may not disclose the quality of the components or connections there between. For example, it may not detect a poor weld connection between components within the thermal battery. Thus, additional systems, methods, and devices are needed to facilitate non-destructive testing of thermal batteries.